I restored these ages ago, cosmetically they're a bit messy but functionally they're in good shape.

I used original domes and some newer soft dome tweeters and I rather like the results.

Ah, a bit disappointed at the lack of detail there, my friend. Photos would be nice. I'm always interested in AR designs, which certainly got something extremely right. To a modern eye they look unsophisticated, especially the paper tweeters. But recall the AR-3A was one of the most respected speakers of its time using the now unfashionable acoustic suspension bass.

Without having done any modelling of some of those simple crossovers, it certainly looks like they were quite a lot more time-aligned than other designs. They also seem to have less places for energy to be stored, resulting in a very immediate and lively presentation.

What I'm getting at, is that one approach is to seek out the original drivers and similar crossover components. The other is to fully understand how the design worked, and use modern components with the same properties. For instance it stands out to me that the AR3-A used paper dome tweeters. Now that is interesting. I don't know what the midrange domes were made of, do you?

I took some photos at the time, i'll see about digging them up later with a bit of commentary on what I did.

I just installed the new drivers, fixed some wiring faults in the crossovers, cleaned out the pots and put it all together again. The only tricky bit was sealing which required some new gaskets which I just cut from a foam packing bag. The surrounds are cloth not foam so did not need replacing.

I still prefer my big Celestion 662, but they came out surprisingly nice for a pair of their age

The Celestion 66, which I know well enough was not a million miles away from the AR-3A. I notice a third order tweeter there. It so depends on the acoustic rolloff of the drivers, but both have something going for them.

For sure putting a dome midrange next to the tweeter is a sweet combination.

Ah, a bit disappointed at the lack of detail there, my friend. Photos would be nice. I'm always interested in AR designs, which certainly got something extremely right. To a modern eye they look unsophisticated, especially the paper tweeters. But recall the AR-3A was one of the most respected speakers of its time using the now unfashionable acoustic suspension bass.

Without having done any modelling of some of those simple crossovers, it certainly looks like they were quite a lot more time-aligned than other designs. They also seem to have less places for energy to be stored, resulting in a very immediate and lively presentation.

What I'm getting at, is that one approach is to seek out the original drivers and similar crossover components. The other is to fully understand how the design worked, and use modern components with the same properties. For instance it stands out to me that the AR3-A used paper dome tweeters. Now that is interesting. I don't know what the midrange domes were made of, do you?

Well, the inventor of many hifi things and among others the "dome" , mr. Edgar Villchur, who was the founder of Acoustic Research unfortunately died autumn 17. october 2011.
His paperdome and coil in the AR3 and AR3a tweeter is situated with only 3 dots of an unknown glue, and deliver/delivered a wide soundperspective which in the 1950 'es was very difficult to obtain with elipse or round papercone speakers. The midrange has a fabric clothdome and a piece of something like glasswool to reduce reflections. Mr Villchur used a lot of time and messurement to get the three units in the AR3a to work together. Because of this work the crossover became rather simple, and the AR3a produces easily what we all like: "A very presize stereo window".

The sound from AR3a is authoritative and one of the best...I think. Try " Jet Set" with Grateful Dead, then you know what I mean.
Rgds.

You've reminded me of something I've been meaning to do for some time, which is remove the crossovers and draw out the schematic for them, note they're 662 not 66 so they differ to some degree. I've never found full proper specifications of crossover schematic for the 662.

I've had them for a few years now, keeping them in repair has been somewhat more exciting though not challengingly so, one of the tweeters blew so I took it apart and rewound the coil, the mid dome also became misaligned and was easily fixed by centring it. I wrote both repairs up and I believe they're in my post history.

Yes, you are right! mirrored pairs would have been better....I think.
I have a very rare pair spare set of AR3a in light birch veneer, and I like the dark rosewood better. My thought was to built a new pair of AR3a cabinets by use of MDF hardwood and with dark rosewood veneer. At this point it was possible to make them mirrored.
Rgds.